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.\"     @(#)tcopy.1	8.2 (Berkeley) 4/17/94
.\" $FreeBSD: src/usr.bin/tcopy/tcopy.1,v 1.7 2000/03/01 12:20:12 sheldonh Exp $
.\"
.Dd April 17, 1994
.Dt TCOPY 1
.Os BSD 4.3
.Sh NAME
.Nm tcopy
.Nd copy and/or verify mag tapes
.Sh SYNOPSIS
.Nm
.Op Fl cvx
.Op Fl s Ar maxblk
.Oo Ar src Op Ar dest
.Oc
.Sh DESCRIPTION
.Nm Tcopy
is designed to copy magnetic tapes.  The only assumption made
about the tape is that there are two tape marks at the end.
.Nm Tcopy
with only a source tape
.Pf ( Ar /dev/nst0
by default) specified will print
information about the sizes of records and tape files.  If a destination
is specified a copy will be made of the source tape.  The blocking on the
destination tape will be identical to that used on the source tape.  Copying
a tape will yield the same output as if just printing the sizes.
.Pp
Options:
.Bl -tag -width s_maxblk
.It Fl c
Copy
.Ar src
to
.Ar dest
and then verify that the two tapes are identical.
.It Fl s Ar maxblk
Specify a maximum block size,
.Ar maxblk .
.It Fl v
Given the two tapes,
.ar src
and
.Ar dest
verify that they are identical.
.It Fl x
Output all informational messages to the standard error.
This option is useful when
.Ar dest
is
.Pa /dev/stdout .
.El
.Sh SEE ALSO
.Xr mtio 4
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.3 .
.Sh BUGS
Writting an image of a tape to a file does not preserve much more than
the raw data.
Block size(s) and tape EOF marks are lost which would
otherwise be preserved in a tape-to-tape copy.

EOD is determined by two sequential EOF marks with no data between.
There are old systems which typically wrote three EOF's between tape
files.
.Xr tcopy 1
will erroneously stop copying early in this case.

When using the copy/verify option \-c
.Xr tcopy 1
does not rewind the tapes prior to start.
A rewind is performed
after writing prior to the verification stage.
If one doesn't start
at BOT then the comparison may not be of the intended data.
